Dental chair.



Patented Nov. 28, I899. G. T. HIGGINS.

DENTAL CHAIR.

(Application filed Feb. 4, 1897.)

5 Sheets-$heet 2.

I, VIII,II"I"II In: NORRIS PETERS co. PFOYD-LYTHO. WASNINGTON, n. z:v

(No Model.)

No.-- 6-38,l9?. Patented Nov. 28, I899;

G. T. HIGGINS.

DENTAL CHAIR.

(Application filed Feb. 4, 1897.) (No Model.) 5 Sheets-Sheet 3.

Tu: VNQECRIS Pmas o0; Wife-union wuumm-ou, u. c.

No. 638,!97. Patented Nov. 28, I899.

' G. T HIGGINS.

DENTAL CHAIB.

(Application filed. Feb. 4, 1897.)

5 Shaets$heat 4.

(No Model.)

Patented Nov. 28, was. a. T. mas-ms- DENTAL CHAIR.

(Application filed Feb. 4, 1897.)

(No Model.)

5 Sheets-Shani 5.

Inventor.

Attorncyy ME nomus PKIERS w. PHOTO-LITHO. WASHINGTON, u. c.

, drawn on the line t of Fig. 6.

PATENT tries.

GEORGE T. HIGGINS, OF MILWAUKEE, I/VISCONSIN.

DENTAL CHAIR.

SPECIFICATION forming part of Letters Patent No. 638,197, dated November28, 1899.

Application filed February 4, 1897- Serial No. 621,963. (No model.)

T0 on whom it may concern.-

Be it known that I, GEORGE T. HIGGINS, a citizen of the United States,residing at Mil- Waukee, in the county of Milwaukee and State ofWisconsin, have invented new and useful Improvements in Dental Chairs,of which the following is a specification.

My invention relates to improvements in dental chairs.

The objects of my invention are, first, to provide improved means foradjusting the chair, and, second, to provide means for converting thesame into an operating-table.

In the following description reference is had to the accompanyingdrawings, in which- Figure 1 is a side view of myimproved chair. Fig. 2is a top view of the foot-rest. Fig. 3 is a detail section view of thesame. Fig. 4: is a top view in section, drawn on the line on m ofFig. 1. Fig. 5 is a central vertical longitudinal section view with themain standard and base-plate omitted. Fig. 6 is a partial top view insection, drawn on the line 3 y of Fig. 1. Fig. 7 is a detail top view ofthe crosshead of the jack for supporting the back of the seat. Fig. 8 isa detail vertical section of the lifting-jack, d rawn on the lines zofFig. 6. Fig. 9 is a view of the outer or rear section, Fig. 10 is a rearview of the chair-back. Figs. 11 and 12 are cross and vertical sectionalviews, respectively, of the lower portion of the pistoncylinder. Figs.13, 14: and 15 are side and section views of my improved form of caster.Fig. 16 is a section view in detail, illustrating a modified form oflocking device for the standard I. Fig. 17 is an enlarged front view ofthe foot-rest with the forward portion thereof removed, on a line alongthe lower edge of the member T, and with a portion of the member Tbroken away to show the actuating mechanism. Fig. 18 is a side viewsimilar to that given in Fig. 3, but also enlarged, and with the parts Tand T shown in the opposite extreme.

Like parts are identified by the same reference-letters throughout theseveral views.

The chair-seat is located within a cast body A, which is hinged to andsupported at a a on the cross-head B of a plunger B of a jack located inthe standard 0. The chairbody is tilted on its pivotal support to thedesired position and is held in place by a bellcrank lever 19, carriedby the cross-head B, and having a pin which engages in holes or notchesin a bracket C, carried by the body A. These parts, as well as themechanism for operating the jack, may be of any ordinary construction,and are therefore not described with particularity.

The seat D and seat-back E are hinged together at e, and the seat is atits front end pivotally attached to the body at cl d, the seat-back Ebeing supported at its upper end by the studs fof the vertical bars f,attached to the cross-head F of the adj listingjacks located in the rearportion of the body A.

As a preferred form of lifting-jack, the cross-head F is provided with adepending rack-bar L, located at one side of the piston cylinder andadapted to be engaged by a bellcrank pawl L, pivoted at the outer end ofa lever M, which is fulcrumed to the body of the chair at m. The pawl Lis normally held out of engagement with the rack by means of aretracting-spring M.

N is a foot-lever for lifting the rack, connected to the outer arm ofthe bell-crank by a rod N and adapt-ed by its initial movement to throwthe pawl into engagement with the rack and by its continued movement tolift the rack, with the cross-head and back, to the chair upon the leverM. On removing the foot the levers are restored to their normalpositions by the spring M, and the cross-head is sustained in its raisedposition by the liquid which enters the cylinder of the loweringjack, ashereinafter described.

In the lowering-jack, G is a liquid-chamber provided with a cylindricalextension G. H is a piston-cylinder located in the cylinder G andprovided with a valved inlet h at its lower end, through which theliquid enters the cylinder during the upward movement of the piston. Iis the plunger or piston, to the upper end of which the cross-head F isattached, and J is a small pin-valve in the bottom of the cylinder H,actuated from the lever J by means of a rod j, arm j, link j, lever K,and connecting-rod K to slowly release the liquid from thepiston-cylinder when it is desired to lower the chair-back. The lowerend of the piston-rod is provided'with leather or rubber rings 5 i,which serve as a packing, and near the upper end of the rod is amovablewasher I, which prevents the liquid from following the rod to itsupper extremity.

For extending the back I have provided the cross-head F with avertically-disposed bar 0, offset rearwardly from the cross-headsufficiently to clear the chair-body at its lower end and provided atits outer surface with a dovetail flange 0. This flange is slidinglyengaged by the counterpart flanges of a standard P, the latter beingprovided with arms P at its upper end, adapted to support a frame Q inthe rear of the upper end of the seatback.

The upholstery Q is extended over the back of the seat and looped overand around the frame, as shown in Figs. 1 and 10, with its tinuation ofthe back of the seat.

end attached to the upper end of the seatback in front of the frame.That portion of the upholstery between the frame and the back of theseat consists merely of the web or covering without any filling.

It will be observed that as the upholstery is attached to the back ofthe seat at both ends and merely looped around the frame the effect ofraising the frame above the sea t-back is to draw that portion of theupholstery which is in the rear of the frame over the top and onto thefront side, the upward-projecting portion of the raised frame being thuscovered by the upholstery and forming a con- The extension of theupholstery on the front side of the frame will of course correspond withthe shortening of the web underneath the frame or between the frame andthe seat-back as this portion is drawn out upon the rear side of theframe.

The standard is locked at any desired point or adjustment by means of asetscrew q or y by a ball q, located in a wedgeshaped socket,

as shown in Fig. 16.

With the latter construction the standard can be pulled up readily, butcan only be lowered by first raising it slightly and then depressing itwith a quick movement or jerk, which will cause the ball to slip.

The head-rest R is supported by a standard R, adjustably attached to theouter surface of the standard P in the same manner as the standard P issupported on the bar 0.

The foot-rest of my chair is provided with an angularlyshaped casting S,depending from the front end of the body A. \Vithin this casting I havelocated an adjustable frame comprising two members T and T, hingedtogether at 25 and to the body A at 25. For adjusting this frame I haveprovided the casting with a rack U in the rear of the member T of theframe, and this rack is engaged by a pawl U, attached to a rod U, whichextends to the side of the casting S and is provided with a foot-plate Von the exterior, the parts being provided with suitable guides toprevent cramping. A bar W, attached to the lower member T of thefoot-frame, is also attached to the rod U by a connecting-bar XV, sothat the downward movement of the foot-plate V, with the rod U and pawlU, will cause the members T and T to swing out on the hinges t away fromthe casting. With the continued downward movement of the foot-plate themembers T and T are alined, as shown in Fig.18. The connecting-bar Wswings outwardly and stands at a considerable angle to the rack U, thusfurnishing a brace for the alined members T and '1".

In manipulating my chair, assuming the parts to be in the position shownin Fig. 1 and it being desired to adjust them to the other extreme inorder to form an operatingtable, I first extend the back by looseningthe set-screw q and raising the standard P, with its supported frame Q,above the back of the seat. The head-rest being supported from thestandard P will be raised with it, but can then be adjustedindependently by readjusting the standard R upon the standard P. Thestandards being locked in the desired positions by means of set-screws,I tilt the chair backwardly upon the cross-head B of the basestandard,and then by applying the pressure of the foot to the lever N of thelifting-jack above described the pawl L is actuated to engage with andlift the rack L, with the crosshead F and the back of the chair-seatsupported therefrom. The seat being hinged to the back at its rear endwill also be tilted upon its pivotal supports 01 d, and with thecontinued upward movement caused by the lifting-jack the seat and itsback will be brought into substantial alinement. The force applied tothe foot-lever N may be removed at intervals, if desired, and the entirechair readjusted or additionally tilted upon the cross-head B inaccordance with the altered position of the seat. If the parts of thefoot-frame be now adjusted outwardly and alined, they will also bealined with the seat and its back, and the chair being sufficientlytilted upon the cross-head B of the main standard the alined parts willbe brought into a horizontal position, thus forming an operating-tablewhich may be adjusted to any desired height by means of the jack in themain standard. It will be observed that when the lever N is actuated tolift the cross-head F the piston I of the lowering-jack, which dependsfrom the cross-head, will also be lifted, thus drawing the liquid intothe cylinder H through the check-valve 7t and furnishing meansforsupporting the cross-head when the pressure is removed from the footlever. When it is desired to restore the chair to its original position,the lever J is shifted to actuate the pin-valve J to slowly release theoil from the piston-cylinder, and the chair gradually reassu mes itsposition as a seat without shock or jar. The chair is then tiltedforwardly and the foot-frame lowered to its original position by tiltingthe foot-plate to release'the pawl, thus restoring the chair to itsnormal position.

ICC

It will be understood that the object of providing separate lifting andlowering mechanism for the seat and its back is to enable the parts tobe quickly adjusted in the horizontal position and slowly readjusted tothe upright position. Thus I am enabled by successive movements of thefoot-lever N to raise the back of the chair sufficiently to aline theback and its seat, while the return movement, due to the escape of theliquid from the pistoncylinder, is very slow and gradual, and for thisreason I prefer to use the lever-actuated lifting-jack instead ofpumping the liquid into the piston-cylinder for the purpose of raisingthe back, as would be the case with an ordinary hydraulic jack.

It is evident that when the chair is used as a table it is often desiredto change its position in the room, and the ordinary form of caster isfound inadequate, as requiring too great an exercise of force to startit, and when started it often moves suddenly and jars the patient. Ihave therefore provided an improved form of caster, which consists in ashank X, provided with a socket in which the ball-roller Y is set upon abearing of small balls Y. The balls are held in place by aninwardly-converging shoulder, burnished or compressed to form a closebearing for the ball-roller at a point below its center.

Having thus described myinvention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a dental chair, the combination with the body A, located uponapivotal support, a seat fulcrumed at its front end to the body, aseat-back hinged at its lower end to the chairseat, one or moreadjusting-jacks, located in the rear of said seat-back and provided witha cross-head from which the upper end of the seat-back is pivotallysupported, substantially as described.

2. In a dental chair, the combination with the body A, located upon apivotal support, of a seat fulcrumed at its front end to the body, aseat-back hinged at its lower end to the chair-seat and one or moreadjusting-jacks, located in the rear of the seat-back and provided witha cross-head having upwardlyprojecting arms, adapted to pivotallysupport the seat-back at its upper end, substantially as described.

3. In a dental chair, the combination with the body A, located upon apivotal support, of a chair-seat fulcrumed at its front end to the body,a seat-back hinged at its lower end to the chair-seat, a lever-actuatedlifting-jack and a hydraulic lowering-jack, located in the rear of thechair-seat, and a cross-head for said jacks provided with arms adaptedto pivotally support the seat-back, substantially as described.

4. In a dental chair, the combination with the body A, located upon apivotal support, of a seat fulcrumed at its front end to the body, aseat-back hinged at its lower end to the seat, one or more jacks,located in the rear of said seat back and provided with a cross-head,from which the upper end of said seat-back is pivotally supported, astandard adjustably attached to the said cross-head, and anextension-frame supported therefrom, over which the upholstery islooped, whereby as said standard is raised, the back of the chair-seatis extended, substantially as described.

5. In a dental chair, the combination with the body A, located upon apivotal support, of a seat, fulcrumed at its front end to the body, aseat-back hinged at its lower end to the seat, one or more adjusting-jacks, located in the rear of said seat-back and provided withacross-head from which the back is supported, and anextension-frame adjustably supported from the cross-head, over which the upholstery islooped, whereby said seat-back may be extended or shortened at pleasure,substantially as described.

6. In a dental chair,'the combination with the body A, located upon asuitable support, of a seat and its back located therein, one or morejacks for adjusting the position of the seat and its back, avertically-disposed bar connected with the movable portion of said jackor jacks, an extension-frame for the seat-back,adjustably attached tothe said bar, and suitable upholstery looped over said extension-frameand attached to the seat-back at both ends, substantially as described.

7. In a dental chair, the combination with the seat-back, of a movableextension-frame, located in the rear thereof, and suitableupholsterylooped over said frame and attached at both ends to the back of theseat, substantially as described.

8. In a dental chair, the combination with the seat-back, of a movableextension-frame, located in the rear thereof, suitable upholstery loopedover said frame and attached at both ends to the back of the seat, and aheadrest adj ustably attached to the supportingstandard of theextension-frame,substantially as described.

9. In a dental chair, a foot-rest, comprising a cast body rigidlysecured to the body of the chair, a jointed foot-frame pivoted to thebody of the chair and depending therefrom, a bar secured to the lowermember of the foot-frame, and a connecting-bar hinged thereto, a rockingshaft supported from the upper end of the connecting-bar and projectinglaterally at the side of the foot-frame, a depending rack secured to thecasing, and a pawl attached to the rocking shaft and adapted to engagesaid rack, whereby with the downward movement of said shaft and pawl,the members of the foot-frame are thrown outwardly and alined, andsupported in that position, substantially as described.

10. In a dental chair, the combination of a body, located upon anadjustable support, a seat and seat-back, hinged together, with thefront end of the seat fulcrumed upon the chair-body, and an adjustablesupport for the seat-back, adapted to lift the same in relation t0 thechair-body, to aline the seat and its back, substantially as described.

11. In a dental chair, the combination of a body, located upon anadjustable support, a seat and seat-back, hinged together, with the seatfulcrumed at its front end upon the chair-body, an adjustable supportfor the seat-back, adapted to lift the same in relation to thechair-body, to aline the seat and its back and an adjustablefo0t-frame,adapted to be alined with the seat and its back, said bodybeing arranged to tilt upon its support suflieiently to bring the alinedparts into a horizontal position, substantially as described.

In testimony whereof I affix my signature in the presence of twoWitnesses.

GEORGE T. HIGGINS.

Witnesses:

JAs. B. ERWIN, LEVERETT 0. WHEELER.

